The present invention relates to a grain cart or wagon having a hopper or container with a discharge auger conveyor and of the general type disclosed in U.S. Pat. No. 5,340,265, U.S. Pat. No. 6,296,435 and U.S. Pat. No. 7,134,830 which issued to the assignee of the present invention. In such a grain cart or wagon, herein referred to as a grain cart, it is desirable to have an overall width no greater than 12 feet and an overall height under 13 feet in order to provide for conveniently transporting the grain cart along a roadway or on a semi-trailer without removing wheels or obtaining a special wide-load road permit which is costly, time consuming to obtain and requires at least one escort vehicle. It is also desirable for the grain cart to accept grain from an auger projecting from a combine having a wide crop gathering head, for example, up to 40 feet wide and while the cart is moving along side the moving combine.
Commonly, the grain transfer auger on the combine is not long enough to reach much further than the grain gathering head on the combine and into the container of the cart by a distance which provides for desirable load distribution of the grain within the container, especially while the cart is traveling along side the combine during transfer of grain from the combine to the cart container. If the cart is pulled by the tow tractor close to the combine, there is a likelihood that the wheels on the grain cart will collide with the combine gathering head. While some grain cart manufacturers have produced grain carts with side board extensions secured to the top of the grain cart container side walls, the carts have an overall width greater than 12 feet and/or an overall height which is too high to accommodate the discharge auger on many existing combines in order to fill the cart container properly.